Energetic nanofluid fuel has caught the attention of the field of aerospace liquid propellant for its high energy density(HED), but it suffers from the inevitable solid-liquid phase separation problem. To resolve this...Energetic nanofluid fuel has caught the attention of the field of aerospace liquid propellant for its high energy density(HED), but it suffers from the inevitable solid-liquid phase separation problem. To resolve this problem, herein we synthesized the high-Al-/B-containing(up to 30%(mass)) HED gelled fuels, with low-molecular-mass organic gellant Z, which show high net heat of combustion(NHOC), density, storage stability, and thixotropic properties. The characterizations indicate that the application of energetic particles to the gelled fuels obviously destroys their fibrous network structures but can provide the new particle-gellant gelation microstructures, resulting in the comparable stability between 1.0%(mass) Z/JP-10 + 30%(mass) Al or B and pure JP-10 gelled fuel. Moreover, the gelled fuels with high-content Al or B exhibit high shear-thinning property, recovery capability, and mechanical strength, which are favorable for their storage and utilization. Importantly, the prepared 1.0%(mass) Z/JP-10 + 30%(mass) B(or 1.0%(mass) Z/JP-10 + 30%(mass) Al) shows the density and NHOC 1.27 times(1.30) and 1.43 times(1.21)higher than pure JP-10, respectively. This work provides a facile and valid approach to the manufacturing of HED gelled fuels with high content of energetic particles for gel propellants.展开更多
Soy flour(SF),soy protein and soy protein isolates(SPI)have been the focus of increasing research on their application as new materials for a variety of applications,mainly for wood adhesives and other resins.Tannins ...Soy flour(SF),soy protein and soy protein isolates(SPI)have been the focus of increasing research on their application as new materials for a variety of applications,mainly for wood adhesives and other resins.Tannins too have been the focus of increasing research for similar applications.While both materials are classed as non-toxic and have achieved interesting results the majority of the numerous and rather inventive approaches have still relied on some sort of hardeners or cross-linkers to bring either of them or even their combination to achieve acceptable results.The paper after a presentation of the two materials and their characteristics concentrates on the formation of gels,gelling and even hardening in the case of soy-tannin combined resins.The chapter than finishes with details of the formation of resins giving suitable wood adhesive of acceptable performance by the covalent coreaction of soy protein and tannin without any other hardener,thus totally bio-sourced,non-toxic and environment friendly as a base of further advances to expect in future by these two materials combination.展开更多
Gelled fuels are the very promising propellants for new-generation rocket and ramjet propulsion.Here we report a new type of low-molecular mass organic gellant(Z),and prepared four kinds of stable gelled fuels based o...Gelled fuels are the very promising propellants for new-generation rocket and ramjet propulsion.Here we report a new type of low-molecular mass organic gellant(Z),and prepared four kinds of stable gelled fuels based on HD-01,HD-03,RP-3 and QC liquid fuels,with the critical gellant concentration less than 1%(mass).The characterizations show that the gellant can form 3D network structure,via hydrogen bonding,π-πstacking and van der Waals forces,to fix fuel molecules during the formation of gelled fuels.So,the gelled fuels show high stability,with the remaining gel mass of 0.25%(mass)Z/HD-01 more than 90%even at high centrifugal speed of 7500 r·min^(-1),but the rheological property test shows that all gelled fuels have obvious shear thinning property,which benefits its storage in gelled state while supply in liquid state.The gelation of liquid fuels by gellant Z can increase the volumetric net heat of combustion(for HD-01,it increases from 39.58 MJ·L^(-1) to 40.76 MJ·L^(-1) with 1%(mass)Z),and liquefied gelled fuels show the comparable ignition delay time with the pristine liquid fuels.So,the gelled fuels made by gellant Z have better stability,shear thinning and combustion performances,which have great potential for the practical application.展开更多
In order to research start-up pressure wave propagation mechanism and determine pressure wave speed in gelled crude oil pipelines accurately,experiment of Large-scale flow loop was carried out.In the experiment,start-...In order to research start-up pressure wave propagation mechanism and determine pressure wave speed in gelled crude oil pipelines accurately,experiment of Large-scale flow loop was carried out.In the experiment,start-up pressure wave speeds under various operation conditions were measured,and effects of correlative factors on pressure wave were analyzed.The experimental and theoretical analysis shows that thermal shrinkage and structural properties of gelled crude oils are key factors influencing on start-up pressure wave propagation.The quantitative analysis for these effects can be done by using volume expansion coefficient and structural property parameter of gelled crude oil.A new calculation model of pressure wave speed was developed on the basis of Large-scale flow loop experiment and theoretical analysis.展开更多
Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect (reacting with polymers),...Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect (reacting with polymers), and then the injection profiles are significantly modified. At present, research on gelled particles is mainly focused on laboratory studies of drive mechanisms, and rarely on mathematical models describing the blocking process of gelled particles. In this paper, the blocking process of gelled particles is divided into two sub-processes: deposition and desorption due to particle deformation. A mathematical model based on filtration theory is proposed considering the effect of characteristics of gelled particles on the blocking process. Blocking laws were simulated and researched using the mathematical model. Results of the simulation of the blocking of gelled particles are quite consistent with the experimental results, which confirms the reliability of the mathematical model developed.展开更多
Reference electrodes are a key part for corrosion monitoring and measurement of rebars in concrete. A reference electrode that can be buried in concrete is fabricated by using Ag/Ag Cl electrode and methyl cellulose g...Reference electrodes are a key part for corrosion monitoring and measurement of rebars in concrete. A reference electrode that can be buried in concrete is fabricated by using Ag/Ag Cl electrode and methyl cellulose gelling electrolyte. The stability, repeatability and anti-polarization of the reference electrode are investigated; the influences of the inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are also investigated in this paper. The results show that the reference electrode has good stability, repeatability, and antipolarization. The influences of inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are minimal. Therefore, it can be used for corrosion monitoring and measurement of rebars in concrete.展开更多
Encapsulation confers protection to substances as essential oils from processes like oxidation, evaporation or uncontrolled release. In this study almond oil capsules were obtained by co-extrusion/gelling technique. C...Encapsulation confers protection to substances as essential oils from processes like oxidation, evaporation or uncontrolled release. In this study almond oil capsules were obtained by co-extrusion/gelling technique. Chitosan was used as shell material and sodium triphosphate pentabasic as cross linking agent. Different encapsulation process variables were studied: cross-linker concentration, nozzles size and potential. Optical microscopy was used to determine the capsules morphology and degradability tests were performed in order to study capsules degradation over time. Results showed that nozzles size and cross linking concentration are key variables to consider in the encapsulation process. Degradability tests showed rapid weight loss.展开更多
An in-situ consolidation method was developed and optimized to successfully fabricate alumina ceramics using pre-gelling starch. Our results showed that the obtained ceramics have more homogeneous microstructure, high...An in-situ consolidation method was developed and optimized to successfully fabricate alumina ceramics using pre-gelling starch. Our results showed that the obtained ceramics have more homogeneous microstructure, higher density, higher flexural strength, and favorable biocompatibility compared to the regular one. During the process, cornstarch granules swelled and deformed but no fracture was observed. After the cornstarch granules bursted, alumina particles were suspended uniformly in the three-dimensional network structure to generate a much smoother surface. Below 0.5 wt% higher cornstarch content increased the flexural strength of prepared ceramics, while above 0.5 wt% the mechanical properties were compromised. Therefore the cornstarch content of 0.5% was the optimal concentration to achieve the highest mechanical strength of the prepared ceramics, with a measured flexural strength of 341 MPa, and a relative density of 96.01%.展开更多
An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and at the same time allow a sustained release. This ...An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and at the same time allow a sustained release. This work analyzed and characterized the rosemary essential oil microcapsules prepared by co-extrusion technique using alginate as wall material and calcium chloride as cross linker. Several instrumental techniques were used: optical microscopy, coulter counter, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), termogravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that rosemary oil has pesticidal properties, and its microencapsulation allows knowing that these properties remain inside the microcapsules.展开更多
In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relativ...In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T °C), and time (t) were fixed to 1:25 (w/v), 75°C, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.展开更多
Thermo-respansive chitosan hydrogel system (TRCHS) was prepared and its mierostructure was investigated by scaning electron microscope (SEM) and mercury intrusion poremaster (MIP). Based on analyzing the data, a...Thermo-respansive chitosan hydrogel system (TRCHS) was prepared and its mierostructure was investigated by scaning electron microscope (SEM) and mercury intrusion poremaster (MIP). Based on analyzing the data, a special porosity property was reported at the first time. Its gelling mechanism was studied by a group of contrast experiments. Results may provide experimental and theoretical supports for how to apply it on tissue engineering scaffold and how to influeuee or control its essential properties.展开更多
The microcapsules containing the artificial diet for tropical fishes were prepared with the spray gelling method in order to prevent water environmental pollution. The carboxymethyl cellulose sodium aqueous solution, ...The microcapsules containing the artificial diet for tropical fishes were prepared with the spray gelling method in order to prevent water environmental pollution. The carboxymethyl cellulose sodium aqueous solution, in which α-tocopherol droplets containing the powdery artificial diet were dispersed, was dropped or sprayed into the chitosan aqueous solution. Microcapsules were prepared by forming polyionic complex shell made from chitosan and carboxymethyl cellulose sodium. In the experiment, the concentration of carboxymethyl cellulose sodium (CMCNa) was mainly changed to investigate the effect on the diameters of microcapsules, the content and the microencapsulation efficiency. The microcapsules couldn’t be prepared with the concentration of carboxymethyl cellulose sodium less than 3.0 wt%. The microcapsules were the core-shell type. The diameters of microcapsules were increased with the concentration of CMCNa and the microencapsulation efficiency of ca. 100% could be obtained by the preparation method presented in this study. The microcapsules were found to be eaten well by tropical fishes and to prevent water environmental pollution.展开更多
An investigation has been made to study the reaction kinetics of gelled acids with calcite using a rotating disk apparatus. The rheological experiments revealed that all gelled acids behaved as non-Newtonian shear thi...An investigation has been made to study the reaction kinetics of gelled acids with calcite using a rotating disk apparatus. The rheological experiments revealed that all gelled acids behaved as non-Newtonian shear thinning fluids. With the rotating disk apparatus, the reaction kinetics parameters, activation energy, and effective diffusion coefficients were determined. It was found that the reaction of gelled acid with calcite was mass transfer limited at low polymer concentration and moving toward surface reaction limited at higher polymer concentration. And the diffusion rate marginally decreased, with increasing the polymer concentration.展开更多
Waxy crude oil is known for its high wax contents that can potentially result in gelling following sufficient cooling of the transportation line in the subsea bed at offshore fields.The gelling over the entire lines r...Waxy crude oil is known for its high wax contents that can potentially result in gelling following sufficient cooling of the transportation line in the subsea bed at offshore fields.The gelling over the entire lines requires an accurately predicted restart pressure to restart the clogged and idle system.However,the common way of predicting the restart pressure has been reported to result in over-designed and predicted piping parameters.Recent research findings evidenced the formation of voids which would reduce the restart pressure significantly.The study conducted in this paper is aimed at investigating the voids size distribution in gelled crude oil across and along transportation pipelines.Sets of experiments simulating crude oil transportation during both static and dynamic cooling were conducted.The gelled crude oil below the pour point temperature was then scanned using a Magnetic Resonance Imaging(MRI)system to detect the voids formed.The resulting voids at each scanning cross-section were quantified,and their distributions were investigated.It was observed that dynamic cooling had minimal impacts on the voids size difference along the pipeline with the difference in voids areas within 10 mm^(2) to be twice and uniform for the entire flow rates tested.However,voids size in statically cooled waxy crude oil was found to be highly distributed with a maximum of 6 voids size distribution in 10 mm2 ranges.The low-end temperature had the highest size difference while the difference was decreasing with higher end temperatures.This study shows that the voids amount in dynamically cooled waxy crude oil could also be estimated with lower numbers of cross-sectional voids areas.However,the higher cross-sectional voids detection is recommended while estimating voids in statically cooled waxy crude oil.展开更多
基金support from the National Natural Science Foundation of China (22222808, 21978200)the Haihe Laboratory of Sustainable Chemical Transformations for financial support
文摘Energetic nanofluid fuel has caught the attention of the field of aerospace liquid propellant for its high energy density(HED), but it suffers from the inevitable solid-liquid phase separation problem. To resolve this problem, herein we synthesized the high-Al-/B-containing(up to 30%(mass)) HED gelled fuels, with low-molecular-mass organic gellant Z, which show high net heat of combustion(NHOC), density, storage stability, and thixotropic properties. The characterizations indicate that the application of energetic particles to the gelled fuels obviously destroys their fibrous network structures but can provide the new particle-gellant gelation microstructures, resulting in the comparable stability between 1.0%(mass) Z/JP-10 + 30%(mass) Al or B and pure JP-10 gelled fuel. Moreover, the gelled fuels with high-content Al or B exhibit high shear-thinning property, recovery capability, and mechanical strength, which are favorable for their storage and utilization. Importantly, the prepared 1.0%(mass) Z/JP-10 + 30%(mass) B(or 1.0%(mass) Z/JP-10 + 30%(mass) Al) shows the density and NHOC 1.27 times(1.30) and 1.43 times(1.21)higher than pure JP-10, respectively. This work provides a facile and valid approach to the manufacturing of HED gelled fuels with high content of energetic particles for gel propellants.
文摘Soy flour(SF),soy protein and soy protein isolates(SPI)have been the focus of increasing research on their application as new materials for a variety of applications,mainly for wood adhesives and other resins.Tannins too have been the focus of increasing research for similar applications.While both materials are classed as non-toxic and have achieved interesting results the majority of the numerous and rather inventive approaches have still relied on some sort of hardeners or cross-linkers to bring either of them or even their combination to achieve acceptable results.The paper after a presentation of the two materials and their characteristics concentrates on the formation of gels,gelling and even hardening in the case of soy-tannin combined resins.The chapter than finishes with details of the formation of resins giving suitable wood adhesive of acceptable performance by the covalent coreaction of soy protein and tannin without any other hardener,thus totally bio-sourced,non-toxic and environment friendly as a base of further advances to expect in future by these two materials combination.
基金the support from the National Natural Science Foundation of China(21978200)the Scientific Research Projects of the Ministry of Education of China(6141A02033522)。
文摘Gelled fuels are the very promising propellants for new-generation rocket and ramjet propulsion.Here we report a new type of low-molecular mass organic gellant(Z),and prepared four kinds of stable gelled fuels based on HD-01,HD-03,RP-3 and QC liquid fuels,with the critical gellant concentration less than 1%(mass).The characterizations show that the gellant can form 3D network structure,via hydrogen bonding,π-πstacking and van der Waals forces,to fix fuel molecules during the formation of gelled fuels.So,the gelled fuels show high stability,with the remaining gel mass of 0.25%(mass)Z/HD-01 more than 90%even at high centrifugal speed of 7500 r·min^(-1),but the rheological property test shows that all gelled fuels have obvious shear thinning property,which benefits its storage in gelled state while supply in liquid state.The gelation of liquid fuels by gellant Z can increase the volumetric net heat of combustion(for HD-01,it increases from 39.58 MJ·L^(-1) to 40.76 MJ·L^(-1) with 1%(mass)Z),and liquefied gelled fuels show the comparable ignition delay time with the pristine liquid fuels.So,the gelled fuels made by gellant Z have better stability,shear thinning and combustion performances,which have great potential for the practical application.
基金Project(2008B-2901) supported by China National Petroleum Corporation
文摘In order to research start-up pressure wave propagation mechanism and determine pressure wave speed in gelled crude oil pipelines accurately,experiment of Large-scale flow loop was carried out.In the experiment,start-up pressure wave speeds under various operation conditions were measured,and effects of correlative factors on pressure wave were analyzed.The experimental and theoretical analysis shows that thermal shrinkage and structural properties of gelled crude oils are key factors influencing on start-up pressure wave propagation.The quantitative analysis for these effects can be done by using volume expansion coefficient and structural property parameter of gelled crude oil.A new calculation model of pressure wave speed was developed on the basis of Large-scale flow loop experiment and theoretical analysis.
基金supported by the National HighTechnology Research and Development Program of China(863 Program)(2007AA06Z214)"Taishan Scholars"Construction Project(No.ts20070704).
文摘Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect (reacting with polymers), and then the injection profiles are significantly modified. At present, research on gelled particles is mainly focused on laboratory studies of drive mechanisms, and rarely on mathematical models describing the blocking process of gelled particles. In this paper, the blocking process of gelled particles is divided into two sub-processes: deposition and desorption due to particle deformation. A mathematical model based on filtration theory is proposed considering the effect of characteristics of gelled particles on the blocking process. Blocking laws were simulated and researched using the mathematical model. Results of the simulation of the blocking of gelled particles are quite consistent with the experimental results, which confirms the reliability of the mathematical model developed.
基金financially supported by the National Science and Technology Support Program of China(Grant No.2011BAG07B04)
文摘Reference electrodes are a key part for corrosion monitoring and measurement of rebars in concrete. A reference electrode that can be buried in concrete is fabricated by using Ag/Ag Cl electrode and methyl cellulose gelling electrolyte. The stability, repeatability and anti-polarization of the reference electrode are investigated; the influences of the inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are also investigated in this paper. The results show that the reference electrode has good stability, repeatability, and antipolarization. The influences of inner electrolyte loss, exterior OH- contamination, and temperature on the potential of the reference electrode are minimal. Therefore, it can be used for corrosion monitoring and measurement of rebars in concrete.
文摘Encapsulation confers protection to substances as essential oils from processes like oxidation, evaporation or uncontrolled release. In this study almond oil capsules were obtained by co-extrusion/gelling technique. Chitosan was used as shell material and sodium triphosphate pentabasic as cross linking agent. Different encapsulation process variables were studied: cross-linker concentration, nozzles size and potential. Optical microscopy was used to determine the capsules morphology and degradability tests were performed in order to study capsules degradation over time. Results showed that nozzles size and cross linking concentration are key variables to consider in the encapsulation process. Degradability tests showed rapid weight loss.
基金Funded by the National Key Research and Development Program of China(Nos.2017YFC1103800,2016YFC1101605)Wuhan Key Science and Technology Project(No.2017060201010191)
文摘An in-situ consolidation method was developed and optimized to successfully fabricate alumina ceramics using pre-gelling starch. Our results showed that the obtained ceramics have more homogeneous microstructure, higher density, higher flexural strength, and favorable biocompatibility compared to the regular one. During the process, cornstarch granules swelled and deformed but no fracture was observed. After the cornstarch granules bursted, alumina particles were suspended uniformly in the three-dimensional network structure to generate a much smoother surface. Below 0.5 wt% higher cornstarch content increased the flexural strength of prepared ceramics, while above 0.5 wt% the mechanical properties were compromised. Therefore the cornstarch content of 0.5% was the optimal concentration to achieve the highest mechanical strength of the prepared ceramics, with a measured flexural strength of 341 MPa, and a relative density of 96.01%.
基金The autors thank IVACE(Institut Valenciàde Competitivitat Empresarial,Spain)FEDER(Fondo Europeo de Desarrollo Regional,Europe)for the financial support
文摘An essential oil is the volatile lipophilic component extracted from plants. Microencapsulation systems protect the essential oil from degradation and evaporation, and at the same time allow a sustained release. This work analyzed and characterized the rosemary essential oil microcapsules prepared by co-extrusion technique using alginate as wall material and calcium chloride as cross linker. Several instrumental techniques were used: optical microscopy, coulter counter, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), termogravimetric analysis (TGA), spectrophotometry, antimicrobial test and chromatography. Results show that rosemary oil has pesticidal properties, and its microencapsulation allows knowing that these properties remain inside the microcapsules.
文摘In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T °C), and time (t) were fixed to 1:25 (w/v), 75°C, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.
文摘Thermo-respansive chitosan hydrogel system (TRCHS) was prepared and its mierostructure was investigated by scaning electron microscope (SEM) and mercury intrusion poremaster (MIP). Based on analyzing the data, a special porosity property was reported at the first time. Its gelling mechanism was studied by a group of contrast experiments. Results may provide experimental and theoretical supports for how to apply it on tissue engineering scaffold and how to influeuee or control its essential properties.
文摘The microcapsules containing the artificial diet for tropical fishes were prepared with the spray gelling method in order to prevent water environmental pollution. The carboxymethyl cellulose sodium aqueous solution, in which α-tocopherol droplets containing the powdery artificial diet were dispersed, was dropped or sprayed into the chitosan aqueous solution. Microcapsules were prepared by forming polyionic complex shell made from chitosan and carboxymethyl cellulose sodium. In the experiment, the concentration of carboxymethyl cellulose sodium (CMCNa) was mainly changed to investigate the effect on the diameters of microcapsules, the content and the microencapsulation efficiency. The microcapsules couldn’t be prepared with the concentration of carboxymethyl cellulose sodium less than 3.0 wt%. The microcapsules were the core-shell type. The diameters of microcapsules were increased with the concentration of CMCNa and the microencapsulation efficiency of ca. 100% could be obtained by the preparation method presented in this study. The microcapsules were found to be eaten well by tropical fishes and to prevent water environmental pollution.
文摘An investigation has been made to study the reaction kinetics of gelled acids with calcite using a rotating disk apparatus. The rheological experiments revealed that all gelled acids behaved as non-Newtonian shear thinning fluids. With the rotating disk apparatus, the reaction kinetics parameters, activation energy, and effective diffusion coefficients were determined. It was found that the reaction of gelled acid with calcite was mass transfer limited at low polymer concentration and moving toward surface reaction limited at higher polymer concentration. And the diffusion rate marginally decreased, with increasing the polymer concentration.
文摘Waxy crude oil is known for its high wax contents that can potentially result in gelling following sufficient cooling of the transportation line in the subsea bed at offshore fields.The gelling over the entire lines requires an accurately predicted restart pressure to restart the clogged and idle system.However,the common way of predicting the restart pressure has been reported to result in over-designed and predicted piping parameters.Recent research findings evidenced the formation of voids which would reduce the restart pressure significantly.The study conducted in this paper is aimed at investigating the voids size distribution in gelled crude oil across and along transportation pipelines.Sets of experiments simulating crude oil transportation during both static and dynamic cooling were conducted.The gelled crude oil below the pour point temperature was then scanned using a Magnetic Resonance Imaging(MRI)system to detect the voids formed.The resulting voids at each scanning cross-section were quantified,and their distributions were investigated.It was observed that dynamic cooling had minimal impacts on the voids size difference along the pipeline with the difference in voids areas within 10 mm^(2) to be twice and uniform for the entire flow rates tested.However,voids size in statically cooled waxy crude oil was found to be highly distributed with a maximum of 6 voids size distribution in 10 mm2 ranges.The low-end temperature had the highest size difference while the difference was decreasing with higher end temperatures.This study shows that the voids amount in dynamically cooled waxy crude oil could also be estimated with lower numbers of cross-sectional voids areas.However,the higher cross-sectional voids detection is recommended while estimating voids in statically cooled waxy crude oil.